Trapezoid mortised genioplasty: A further refinement of mortised genioplasty

The treatment strategies for obstructive sleep apnea (OSA) continue to evolve. Surgical correction of the airway is becoming more routine with therapy targeted to multiple specific levels of obstruction: the nasal passage, oropharynx, and hypopharynx. Early limited success with uvulopalatopharyngoplasty for oropharyngeal obstruction illustrated the important role of hypopharyngeal narrowing in OSA. The genioglossus advancement with hyoid suspension was thus born to address this new challenge. In 1984, Riley et al. described the first genioglossus advancement for OSA. A horizontal sliding genioplasty was performed with concurrent radical transection of the infrahyoid strap muscles. The hyoid was further suspended to the mandible anteriorly and superiorly with fascia lata harvested from the lower extremity. However, early experience demonstrated a high risk of mandibular fracture at the symphysis when the osteotomy was carried high enough to capture the genial tubercle. In 1986, mortise genioplasty with inferior sagittal osteotomies extending up and including the genioglossus tubercle was introduced (Fig. 1A). Although this technique advanced not only the genioglossus but also the geniohyoid, mylohyoid, and digastric muscles, this modification was abandoned due to increased risk of mandibular fracture. Within 5 years of the original description, the inferior mandibular osteotomy, or rectangular or box osteotomy, became the treatment of choice. A rectangular osteotomy with 2-cm horizontal and 1-cm vertical limbs was performed below the lower central incisors, thereby including the entire genioglossus tubercle (Fig. 1B). The segment was advanced and turned to lock the segment into place. The fragment was fixed by a single inferiorly placed miniscrew. Ultimately, criticism of this technique would include limited muscular advancement and inability to provide adequate fixation. In 1999, Prinsell described the anterior inferior mandibular osteotomy (AIMO). Similar to mortised genioplasty, inferior sagittal osteotomies are carried superiorly to include the genial tubercle without compromising the teeth apices. However, the osteotomy is a continuous bone cut with no sharp angles, thus minimizing the risk of fracture (Fig. 1C). The segment is then advanced the bicortical width. An anatomic study 1 year later placed the original mortised genioplasty back into favor. The study detailed the relationship of the genial tubercle to mandibular landmarks and emphasized that the width of the genioglossus muscle is larger than previously thought. Mortised genioplasty was described as a favorable procedure as it allows for maximal muscular attachment anteriorly. Earlier concern for fracture was minimized with lateral fixation, and the design was modified to increase the muscular advancement (Fig. 1D). Further support for mortised genioplasty would follow, reinforcing the maximal suprahyoid musculature advancement. Although mortised genioplasty has advanced our ability to treat hypopharyngeal obstruction, it does carry certain limitations. Functionally, Li et al. emphasized that even when vertical osteotomies are performed as far laterally as the medial edge of the canine roots, the genioglossus fibers are cut even though the tubercle is entirely included. The authors emphasize the From the Craniofacial Center, Department of Plastic Surgery (D.S., C.-H.L., Y.-C.C., Y.-R.C.), Department of Craniofacial Orthodontics (S.S.-P.H.), Craniofacial Research Center (S.S.-P.H., C.-H.L, Y.-C.C., Y.-R.C.), Sleep Center (C.-H.L.), Chang Gung Memorial Hospital, Taoyuan, Taiwan. Editor’s Note: This Manuscript was accepted for publication May 3, 2012. The authors have no funding, financial relationships, or conflicts of interest to disclose. Send correspondence to Cheng-Hui Lin, MD, Sleep Center, Craniofacial Center, Chang Gung Memorial Hospital, 5 Fushing Street, Gueishan, Taoyuan, Taiwan 333. E-mail: clementlin0614@yahoo.com